Method of making long draft aprons



2 P 1949- B. R. BILLMEIYER 2,482,702

METHODDF MAKING LONG DRAFT APRONS Filed July 51, 194-1 mama Sept. 20, 1949 I METHOD OF MAKING LONG APBONS Bruce R. Billmeyer, Lancaster, Pa., auigncr to Armstrong Cork Company, Lancaster, Pa, a corporation of Pennsylvania Application July 31, 1941, 881181 No. 404,782

6 Claims. (of. 154-4) This invention relates to a method of making long draft aprons and more particularly to a method of making a long draft apron including a strengthening and reinforcing layer formed of a plurality of convolutions of twine having applied to the outer surface thereof a wear resistant facing of synthetic rubber. The term twine is used herein to denote strings, threads,

cords, twists, small ropes, spun yarns, or the like of cotton, flax, silk, wool, nylon, glass fibers, rayon, or some other flbrous substance capable of being wound in tubular form.

In my copending application, Serial No. 404,781, filed July 31, 1941, and entitled Long draft aprons, now Patent No. 2,470,599, May 17, 1949, I have disclosed and claimed a long draft apron including a strengthening and reinforcing layer formed of a plurality of convolutionsof twine disposed in tubular form having applied to the outer surface thereof a wear-resistant layer or coating of synthetic rubber composition.

The chief object of the present invention is to provide a method of making long draft aprons of this general type. An object is to provide a method of making long draft aprons which is economical, simply and easily practiced in commercial operation, and which produces an apron more satisfactory than those heretofore known to the industry. A further object is to provide a method of making long draft aprons which obviates the necessity of carrying a large assortment of base fabrics in stock for the manufacture of different sizes of aprons. A still further object is to obviate the difliculties and disadvantages heretofore deemed inherent in the manufacture of long draft aprons.

This invention relates to a method of making long draft aprons for use in fiber drawing in which the steps comprise winding a layer of twine helically about a forming surface to form a cylindrical body and securing a wearing surface of synthetic rubber composition to said body, Preferably, the twine comprises a single layer wound and held in the form of a helix in which adjoining convolutions are disposed in abutting relationship and in which the angles of inclination of the convolutions are within the range of 80-90 from a line drawn axially through the tube and, preferably, are as close as possible to 90,

The attached drawing illustrates a preferredv embodiment of my invention, in which Figure 1 is a view in elevation of the long draft apron of my invention partially broken away to disclose the foundation;

Figure 2 is a diagrammatic view illustrating a method of forming the tubular foundation;

Figure 3 is a diagrammatic view similar to Figure 2, illustrating a method of wrapping a fabric reinforcement about the foundation; and

Figure 4 is a view similar to Figure 1, show ing a long draft apron made in accordance with a modification of my invention.

Referring to the drawing, there is shown in Figure 1 a long draft apron designated generally at 2. The apron 2 comprises a foundation 3 of tubular form, a wear-resistant. layer or coating 4 disposed interiorly thereof, a joining coating F disposed exteriorly thereof and a wear resistant, seamless tubular facing 6 disposed over and integrally united with the foundation 3 through the coating 5.

The foundation 3, preferably, is composed a single length of twine 3a wound helically to form a tube. If desired, a plurality of pieces of twine may be wound in one layer to form a multiple threaded tube; in such case, the true pitch or distance between consecutive convolutions of the same piece of twine is greater than the distance between corresponding points in any two successive convolutions. The convolutions are placed in abutting relationship although, if desired, they may be spaced apart .a', distance not greater than the thickness of the twine'; such abutting or slightly spaced apart relationship of the convolutions is designated herein by the term substantially abutting." The twine may be composed of any natural or synthetic fiber of suitable strength for the purpose intended and cotton, silk, wool, rayon, flax, nylon, or glass fibers are examples of satisfactory materials for my purpose. A typical example ofsatisfactory twine for this purpose is a cotton cord, size #16, four-ply, ten twists to. the inch.

In Figure 2, I have illustrated diagrammatically a method of making the base foundation. There is shown a lathe I of usual type adapted to receive a mandrel I about which the twine 3a is wound or wrapped. A twine holder 9 contains a roll of twine which passes therefrom through Jan eyelet II) to the mandrel 8. The holderli is mounted on a carriage ll actuated by a lead screw I2 connected by suitable gearing (notshown) with the lathe actuating mechanism. The twine holder 9 is movable longiltudinally of the mandrel 8' and, preferably, is

convolution is wound so that the adjacent convolutions abut or are under slight tension.

in the manufacture of the base foundation, the mandrel 3 is coated with a layer of any suitable mold lubricant such as Aquarex D which I believe to be a sodium alkyl sulfate or a suitable soap solution to facilitate removal of the finished tube or apron. The wear-resistant layer 4 isfthen applied to the mandrel .8. Layer 4 is formed of a synthetic rubber composition hereinafter described. An end of the twine 3a is then secured to the mandrel and the lathe l and holder 9 actuated to wind the twine helically about the mandrel 8. Only slight tension need be placed on the twine to ensure satisfactory Winding about the mandrel. The -convolutions are wound in substantially abutting relationship to form the helical tube. The maximum space between convolutions should be no greater than the thickness of the twine for best results and, preferably, the convolutions are disposed in abutting relationship. The convolutions are wound with a slight inclination in either direction, toward the right as shown in Figures 1 and 2, so that the angles formed by the convolutions with a line drawn axially through the tube fall within the range of 80-90, and, preferably, the inclination is as close to 90 as possible. It is desirable that such angles be kept at a maximum to ensure that the base foundation of the apron is substantially inextensible radially. The joining coating 5 is then applied to the wound tube and permitted to dry. The foundation is then in condition to receive the Wear resistant facing 65. Preferably, facing 6 is composed of an extruded, seamless tube of tough, oil and wear resistant synthetic rubber. It will be understood, of course, coating 5 may be dispensed with and the twine impregnated with a solution of a composition similar to the composition of the facing, dried, and wound to form a tube.

The facing is inflated and disposed over the foundation 3 and the combination of foundation 3 and wearing surface layer 8 is wrapped with wet fabric tape in order to obtain engagement of the wearing surface with the base. It is then vulcanized by placing the article in an open steam vulcanizer and applying steam for a period sufficient to cure the mass and to integrally unite the facing, tubular foundation and coatings; for example 30 minutes at 300 F. will be generally satisfactory to obtain the required degree of vulcanization when synthetic rubbers such as Hycar O. R., neoprene, or Thiokol are employed. The article is then removed from the mandrel, the securing tape is removed, and the surface is ground or buffed to a desired diameter. The tubing is then severed to desired length for use as long draft aprons.

The wear resistant tubular facing 6 may be formed of a suitable synthetic rubber composition as shown in the following formula:

Parts by weight This mixture is suitably milled. Thereafter, it is fed to an extrusion machine of the screw type well known to those in the art and a hollow tubular body of desired size is produced adapted to serve as the wearing surface of the long draft apron. If desired, this composition may be calendered to form a thin sheet which is disposed about the wound tube and vulcanized to form a satisfactory seamless wearing surface.

The respective layer and coating 4, 5 may be formed of the above composition in sheet form or dissolved in a suitable solvent such as methyl ethyl ketone, acetone, cyclohexanone, chlorobenzene, chlorotoluene, butyl acetate, or amyl acetate. I have found a coating including 0.8 pound of Hycar to each gallon of solvent is of satisfactory consistency to be brushed in application.

In the above composition Hycar" is a synthetic rubber of the type known as a polymerized butadiene acrylic nitrile copolymer. Other synthetic rubbers may, of course, be employed in forming the wearing surface and coatings 4 and 5, such as Thiokol (olefine polysulfide), neoprene (polymerized chloroprene), Koroseal (plasticized polyvinyl chloride), or similar copolymers containing a high content of chloride such as polyvinyl chloride-acetate copolymers or the like. Any of the materials of this character which possesses high resistance to oil, extreme flexibility and the characteristic of being extremely resistant to cracking upon continued flexing over long periods of time may be substituted. Rubber may be used in some instances where the service does not require a high degree of oil resistance. The method employed in forming the aprons may be varied depending upon the type of synthetic rubber employed; for example, Koroseal does not require vulcanization and aprons having wearing surfaces thereof need not be vulcanized.

In the above described composition, any suitable anti-oxidants may be used and Neozone A (phenyl alpha naphthalamine), Agerite Resin D (polymerized trimethyl dihydro quinoline), Aminox (ketone di-aryl amine), are examples of satisfactory materials. As softeners, I may use tricresyl phosphate, paraflin, dibutyl phthalate} pine tar, cumar, triacetin or the like. Accelerators are well known in the art and mercaptobenzothiazole, tetramethylthiuramdisulfide, diphenylguanidine, zinc butylxanthate, or combinations thereof, for example, may be used. The reinforcing pigments and fillers included in this composition may include any of various grades of carbon blacks, whitings, clays or the like such as Thermax, P-33, fGastex, Kalite, Kalvan, etc. Thermax is a very soft grade of carbon black, P-33 is a soft grade of carbon black somewhat harder than Thermax and Gastex is a hard semi-reinforcing carbon black. Kalvan and Kalite are whitings and differ somewhat in particle size. Zinc oxide is used in the composition primarily as an activator for the accelerators. Stearic acid is used as a plasticizer and aids in vulcanization. Sulfur, of course, is the vulcanizing agent. The ingredients and the amounts used may be varied as desired depending upon the properties required in the completed apron.

It will be understood the base foundation 3 may be laminated, if desired, and composed of a plurality of convolutions of twine extending in one direction and a plurality of convolutions of twine disposed thereover. This is shown in Figure 4 where the inner helical convolutions of twine 3a extend in one direction, and the convolutions 3b extend in the opposite direction, The helically wound twine tube is wound as above described and, if desired, an adhesive layer may be placed between the laminations to assist in retaining the convolutions as a helically wound tube. The tube may be composed of a single length of twine or a plurality of lengths of twine as desired.

In Figure 3, I have illustrated a method of making a modified form of my invention in which a fabric reinforcing and strengthening layer l3 is disposed over the foundation 3 and may be adhesively secured thereto if desired. Preferably, layer I3 is composed of a helically wound strip H of opposite hand to the convolutions of twine composing the tube. In this case, the twine tube 3 is formed on the mandrel 8 in the manner described above and a strip of fabric l4 secured to one end thereof and wrapped helically thereabout with the edges advantages and difliculties heretofore involved in the manufacture of long draft aprons. Th lon draft apron so provided is more satisfactory than any heretofore used in the industry. My method of manufacture permits the base fabric to be subpolymerized chloroprene; wrapping the article so" formed with fabric tape to adhere the wearing surface to the cylindrical bodyof twine, vulcanizing the wearing surface, removing the wrapped tape, and severin said article so formed into' long draft aprons with the severing cuts substan-- tially parallel to the direction of the convolutions of twine to provide a structure in which the twine reinforcing is continuous and uncut throughout essentially the whole axial length of the apron.

3. In the method of making long draft aprons for use in fiber drawing, the steps which comprise disposing an inner wear-resistant layer of synthetic rubber composition about a cylindrical mandrel, helically winding twine about the mandrel to form a laminated tubular bod in which the convolutions of twine in one layer are inclined in one direction while the convolutions of twine in the second layer are inclined in the opposite direction, said twine convolutions bein disposed substantially at right angles to the axis of the cylindrical mandrel, applying a seamless outer wearing surface of synthetic rubber composition over said body, confining the article so formed to join the outer wearing surface to the cylindrical body, vulcanizing the synthetic rubber whil under confinement, releasing the confinement, removing the article from the mandrel and severing the article into long draft aprons with stantially inextensible radially which obviates stretching of the apron in use.

While'I have described and illustrated a preferred embodiment of my invention, it will be understood my invention is not so limited since it may be otherwise embodied within the scope of the following claims.

I claim:

1. In the method of making long draft aprons for use in fiber drawing, the steps which comprise winding a layer of twine helically about a cylinder-forming surface to form a cylindrical body with the twine convolutions disposed substantially at right angles to the axis of the cylinder-forming surface; applying over said body a wearing surface, including as an essential ingredient a synthetic rubber chosen from the group consisting of a polymerized butadiene acrylic nitrile copolymer, a plasticized polyvinyl chloride, 2. plasticized polyvinyl chloride-acetate copolymer, an olefine polysulfide, and a polymerized chloroprene; wrapping the article so formed with fabric tape to adhere the wearing surface to the cylindrical body of twine; vulcanizing the wearing surface; removing the wrapped tape; and severing said article so formed into long draft aprons with the severing cuts substantially parallel to the direction of the convolutions of twine to provide a structure in which the twine reinforcing is continuous and uncut throughout essentially the whole axial length of the apron.

2. In the method of making long draft aprons for use in fiber drawing, the step which comprise disposing a wear-resistant layer of synthetic rubber composition about a cylindrical mandrel; winding 2. layer of twine helically about the mandrel to form a cylindrical body with the twine convolutions disposed substantially at right angles to the axis of the cylindrical mandrel; applying over said body a wearing surface, including as an 75 the synthetic rubber while under confinement,

the severing cuts substantially parallel to the direction of the convolutions of twine to provide a structure in which the twine reinforcing is continuous and uncut throughout essentially the whole axial length of the apron.

4. In the method of making long draft aprons for use in fiber drawing, the steps which comprise disposing an inner wear-resistant layer of synthetic rubber composition about a cylindrical mandrel, winding a length of twine helically over said inner layer to form a cylindrical body of twine with the twine convolutions disposed substantially at right angles to the axis of the cylindrical mandrel, applying a seamless outer wearing surface of synthetic rubber composition over said body, confining the article so formed to join the outer wearing surface to the cylindrical body, vulcanizing the synthetic rubber while under confinement, releasing the confinement, removing the article from the mandrel, and severing the article intolong draft aprons with the severing cuts substantially parallel to the direction of the convolutions of twine to provide a structure in which the twine reinforcing is continuous and uncut throughout essentially the whole axial length of the apron.

5. In the method of making long draft aprons drical mandrel, disposing a coating of synthetic rubber composition over the exterior of said body, applying a seamless outer wearing surface of synthetic rubber composition over said body, confining the article so formed to join the outer wearing surface to the cylindrical body, vulcanizing aeaavoa releasing the confinement, removing the article from the mandrel, and severing the article into long draft aprons with the severing cuts substantially parallel to the direction of the convolutions of twine to provide a structure in which the twine reinforcing is continuous and uncut throughout essentially the axial length of the apron.

6. In the method of making long draft aprons for use in fiber drawing, the steps which comprise disposing an inner wear-resistant layer of synthetic rubber composition about a cylindrical mandrel, helically winding 9. length of twine impregnated with a synthetic rubber composition over said inner layer to form a cylindrical body of impregnated twine with the twine convolutions disposed substantially at right angles to the axis of the cylindrical mandrel, applying a seamless outer wearing surface of synthetic rubber composition over said body, confining the article so formed to join the outer wearing surface with the cylindrical body, vulcanizing the synthetic rubher while under confinement, releasing the confinement, removing the article from the mandrel,

and severing the article into long draft aprons with the severing cuts substantially parallel to the direction of the convoiutions of twine to pro vide a structure in which the twine reinforcing is continuous and uncut throughout essentially the whole axial length of theapron.

3 BRUCE R. BILIMEYER.

REFERENCES crrnn The following references are of record in the file 01 this patent:

UNITED STATES PATENTS Number Name Date 77,173 Crague et al Apt. 28. 1868 192,315 Whittemore et al. June 19, 1877 539,224 Huss May 14, 1895 1,304,694 Marquette -QMay 27, 1919 15 1,422,451 Krausemark July 11, 1922 1,535,647 Brennan Apr. 28, 1925 2,012,223 Cutler Aug. 20, 1935 2,046,136 St. Clair June 30, 1936 2,121,285 Cone June 21, 1938 20 2,170,947 Habgood et a1. Aug. 29, 1939 2,278,424 Campbell Apr. 7, 1942 2,287,780 Carman June 30, 1942 FOREIGN PATENTS 25 Number Country Date 443,642 Great Britain Mar. 2, 1936 

